This invention relates to preparation of a rubber composition by pre-mixing at least one functionalized carbon black with an organic solvent solution or aqueous emulsion of at least one host elastomer. Functionalized carbon blacks for the purposes of this invention preferably contain a functional moiety on their surface to aid in promoting covalent bonds between the functionalized carbon black and said host polymer. The invention also contemplates the use of such rubber composition, or blend of such rubber composition with at least one additional elastomer and/or rubber compounding ingredient, as a component of an article of manufacture. Such article of manufacture may be, for example, a tire. Such article may also be an industrial product such as, for example, a hose or belt such as a conveyor belt or power transmission belt.
Carbon black reinforcement, is conventionally blended with various elastomers with the aid of various internal mixers, as well as open roll mixers, under high sheer and relative high temperature conditions. Accordingly a considerable amount stress is experienced by the rubber composition as well as expenditure of energy to accomplish the aforesaid mixing.
Historically, blends of carbon black and various elastomers have been prepared by various masterbatching processes in which the carbon black is pre-mixed in an aqueous and/or organic solvent medium with one or more elastomers and the resulting pre-mixture dried and then usually mixed with one or more additional elastomers. For example see U.S. Pat. Nos. 3,294,733; 3,298,984; 3,317,458; 3,345,324; 3,491,052; 3,767,605, 3,923,707, 3,350,342, 3,304,281, 3,491,052 and 3,533,988.
However, this invention is directed to pre-modifying typically hydrophobic rubber reinforcing carbon black prior to masterbatching carbon black and diene-based elastomer in an aqueous or organic solvent medium by functionalizing the carbon black to cause it to be more hydrophilic in nature in order to enhance the blending thereof with a diene-based elastomer.
While U.S. Pat. No. 6,136,919 relates to a rubber composition and tire with tread thereof wherein said rubber composition is prepared by polymerization of monomers in the presence of modified carbon blacks to create a reinforced elastomer, such method is not considered herein to be a masterbatching of functionalized carbon black with a diene-based elastomer in an aqueous or organic solvent medium to enhance a covalent binding of the carbon black with its elastomer host.
In the description of this invention, the term xe2x80x9cphrxe2x80x9d relates to parts by weight of an ingredient per 100 parts by weight of rubber.
The terms xe2x80x9crubberxe2x80x9d and xe2x80x9celastomerxe2x80x9d are used interchangeably unless otherwise specified.
The term xe2x80x9cTgxe2x80x9d relates to a glass transition temperature of an elastomer, normally determined by a differential scanning (DSC) calorimeter with a temperature rise of 10xc2x0 C. per minute.